Method for inhibiting occurrence of pyrolysis deposit in pyrolysis gasification system, and pyrolysis gasification system

Abstract

This method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system includes: gasifying biomass (S 2 ) through pyrolysis in a pyrolysis gasification furnace ( 5 ); separating, in a solid-gas separation unit ( 7 ), a pyrolysis gas (G 1 ) and a carbide (C) continuously formed through pyrolysis of the biomass (S 2 ); feeding an oxygen-containing gas (G 3 ) to the separated pyrolysis gas (G 1 ); and introducing the pyrolysis gas (G 1 ) together with the oxygen-containing gas (G 3 ) to a combustion furnace ( 6 ) through a pipe ( 9 ) which constitutes a pyrolysis gas line ( 8 ).

The invention claimed is: 
     
       1. A method for inhibiting occurrence of a pyrolysis deposit in a pyrolysis gasification system, the method comprising the steps of:
 gasifying biomass through pyrolysis in a pyrolysis gasification furnace; 
 separating, in a solid-gas separation unit having a heat resistance, a pyrolysis gas and a carbide continuously formed through pyrolysis of the biomass; 
 feeding an oxygen-containing gas to the solid-gas separation unit during operation of the pyrolysis gasification furnace; and 
 introducing a mixed gas from the solid-gas separation unit to a combustion furnace through a pipe which constitutes a pyrolysis gas line, 
 wherein the mixed gas is a mixture of the pyrolysis gas and the oxygen-containing gas. 
 
     
     
       2. The method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system according to  claim 1 , wherein
 the oxygen-containing gas is a gas having an oxygen concentration of at least 15 volume %. 
 
     
     
       3. The method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system according to  claim 1 , wherein
 the oxygen-containing gas is fed to the pyrolysis gas so that the mixed gas has a temperature of from 500 to 650° C. 
 
     
     
       4. The method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system according to  claim 2 , wherein
 the oxygen-containing gas is fed to the pyrolysis gas so that the mixed gas has a temperature of from 500 to 650° C. 
 
     
     
       5. The method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system according to  claim 1 , wherein
 the oxygen-containing gas is fed to the pyrolysis gas so that a ratio of an actual feed rate of the oxygen-containing gas to a rate sufficient to provide a stoichiometric amount of oxygen for full combustion of hydrocarbons present in the pyrolysis gas is 0.1 or less. 
 
     
     
       6. The method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system according to  claim 2 , wherein
 the oxygen-containing gas is fed to the pyrolysis gas so that a ratio of an actual feed rate of the oxygen-containing gas to a rate sufficient to provide a stoichiometric amount of oxygen for full combustion of hydrocarbons present in the pyrolysis gas is 0.1 or less. 
 
     
     
       7. The method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system according to  claim 3 , wherein
 the oxygen-containing gas is fed to the pyrolysis gas so that a ratio of an actual feed rate of the oxygen-containing gas to a rate sufficient to provide a stoichiometric amount of oxygen for full combustion of hydrocarbons present in the pyrolysis gas is 0.1 or less. 
 
     
     
       8. The method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system according to  claim 4 , wherein
 the oxygen-containing gas is fed to the pyrolysis gas so that a ratio of an actual feed rate of the oxygen-containing gas to a rate sufficient to provide a stoichiometric amount of oxygen for full combustion of hydrocarbons present in the pyrolysis gas is 0.1 or less. 
 
     
     
       9. The method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system according to  claim 1 , wherein
 oxygen-containing gases having different oxygen concentrations are prepared, and an oxygen-containing gas having a low oxygen concentration and an oxygen-containing gas having a high oxygen concentration of the oxygen-containing gases are selectively fed to the pyrolysis gas. 
 
     
     
       10. The method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system according to  claim 2 , wherein
 oxygen-containing gases having different oxygen concentrations are prepared, and an oxygen-containing gas having a low oxygen concentration and an oxygen-containing gas having a high oxygen concentration of the oxygen-containing gases are selectively fed to the pyrolysis gas. 
 
     
     
       11. The method for inhibiting the occurrence of a pyrolysis deposit in a pyrolysis gasification system according to  claim 3 , wherein
 oxygen-containing gases having different oxygen concentrations are prepared, and an oxygen-containing gas having a low oxygen concentration and an oxygen-containing gas having a high oxygen concentration of the oxygen-containing gases are selectively fed to the pyrolysis gas. 
 
     
     
       12. A pyrolysis gasification system comprising:
 a pyrolysis gasification furnace that gasifies biomass through pyrolysis; 
 a solid-gas separation unit that has a heat resistance and separates a pyrolysis gas and a carbide continuously formed through pyrolysis of the biomass; 
 a nozzle that feeds an oxygen-containing gas to the solid-gas separation unit during operation of the pyrolysis gasification furnace; 
 a pipe which is configured to carry a mixed gas from the solid-gas separation unit, the mixed gas being a mixture of the pyrolysis gas and the oxygen-containing gas; and 
 a combustion furnace which is configured to combust the mixed gas, 
 wherein the mixed gas is introduced into the combustion furnace via the pipe.